Semiconductor devices are used in a large number of electronic devices such as computers, cell phones and others. One of the goals of the semiconductor industry is to continue shrinking the size of individual devices. Smaller devices can be fabricated more inexpensively (e.g., since more chips can be formed simultaneously on a single wafer) and can operate at higher speeds (e.g., since the physical distance between components is smaller). As a result, the continual shrinking of components, such as transistors, is desirable.
One process that is commonly used to form semiconductor components is ion implantation. As an example, to form the source and drain of a transistor, dopant ions are typically implanted into a semiconductor body adjacent to a gate. These dopants must then be activated using a thermal process. Any additional thermal processing will cause the dopants to diffuse within the semiconductor body. This diffusion has the consequence of limiting the size of components that include doped regions.
As the gate length is scaled down, it is becoming more and more difficult to adjust performance and leakage. Ultra shallow junctions and improved dopant activation are required. An ultra shallow dopant profile can be formed with the help of laser and flash anneals that activate the dopants without diffusing the dopant species. However, the drastically reduced thermal budget drives up junction leakage since it prevents the annealing of defects, mostly end-of-range (EoR) defects, and leads to extremely hard junctions, which increase band-to-band tunneling (BTBT) and impact ionization (II).